An historic shift of the world population into age groups with increased prevalence of chronic physical diseases, mental disorders and disability is taking place. Chronic physical conditions and mental disorders are both leading causes of disability. Treatable mental disorders and chronic physical conditions often co-occur, but national data concerning their co-morbidity are not available. The extent and nature of disability among persons with specific mental disorders co-morbid with major chronic physical conditions is largely unknown in the population-at-large. There is growing evidence that treating co-morbid mental disorders improves functional outcomes among persons with chronic physical diseases. Unfortunately, efforts to respond to the growing epidemic of chronic disease, mental disorders and related disability are not guided by reliable population-based data. Epidemiological data are urgently needed to guide research, clinical practice, health care organization and public policy in responding to this challenge. In response to PA-02-047 (Research on Co-morbid Mental and Other Physical Disorders), our goal is to address this knowledge gap by determining the extent and nature of disability among persons with mental disorders that are co-morbid with major chronic physical conditions. We will employ data from 28 coordinated national population surveys (N=196,000) participating in the WHO World Mental Health (WMH) initiative. We will study how mood, anxiety, substance use and impulse control disorders influence disability among persons with cardiovascular disease, diabetes, respiratory disorders, arthritis,and chronic pain conditions. The specific aims of this program of research are: Aim 1: Estimate prevalence rates of treatable mental disorders among representative cases with major chronic physical disorders that are leading causes of disability; Aim 2: Advance disability research methods by calibrating WMH disability measures for use in national and international health surveys and health outcomes research; Aim3: Establish the specific contributions of mental disorders to global and specific role disabilities (including work role disability) among persons with major chronic physical disorders; and Aim 4: Determine the effects of physical-mental co-morbidity and social role disability on broader measures of disease burden including health utilities, family burden and stigma.